New Engine Mileage
i am new to his forum. I have a 1982 F350 with a 400 engine. I have a C6 and 3.73 rear end with dual wheels. It is mostly stock except for the edelbrock intake and carb. Both are the performer, no the performance one.
I replaced the engine recently, and my gas mileage has been about 5 mpg, where I got 10 or so before. I had 40 degrees slop in my timing chain. I know that this should be better if anything, but can't figure out what is going on.
I replaced:
engine
radiator
hoses
belts
fuel pump
water pump
starter
distributor
cap
rotor
plugs
This engine was a bear t turn over wheni first got it. Do they loosen up after a while. It was a RECON engine. I am wondering if the mileage will increase sooner or later on it's own...
Do you have any advice?
Thanks,
Mike
The motor will be tight to start with mostly due to the drag created between the rings and the freshly honed cylinder walls.
All the tolerences in the motor are also close (hopefully) which also creates some drag.
It takes a few thousand miles for all the internals to become friends.
Keep a close eye on the oil level, change oil and filter at 1000 miles.
Recheck your timing
Readjust your carburetor
Your mileage will get better!
Good luck!
My truck has a recon in it from S&S in Spokane...they are a good shop that spends real time getting the motor back together, using good parts...but they are more expensive. Basically you get what you pay for.
I like doing my own work because I know it's done right...but I understand the need for the occasional recon engine, especially if you need to get to work on Monday and you blow your motor on Friday night.

Anyways, I think 8 Lugs is right...even a well-build motor will tend to get on the low side of gas milage and oil consumption until things set in. Use a good non-detergent (non-synthetic too!) oil for the first 500 miles, then a good standard oil (again, no synthetic) for the first 2-3000 miles, changing often. After about 3000 miles things should loosen up.
BTW: I use Synthetic oils on all of my vehicles (that are broken in). I strongly recommend it to anyone who has an engine they want to keep for a long time. As long as it's not buring/dripping oil, use a synthetic to keep it like-new.



